This proposal requests funds for the maintenance and minimal care of an indispensable animal resource: a breeding colony of 15 dogs with hereditary narcolepsy (for seven years) and a research colony of 23 narcoleptic dogs for a two-year period. Specifically, it requests funds for the maintenance of a small group of pure-breeding narcoleptic Doberman pinschers that will ensure a reliable and homogeneous supply of dogs for neurochemical, anatomical, and electrophysiological studies. It also requests short-term support of a larger colony of dogs used for pharmacology and breeding studies, pending the development of additional strains of pure-breeding narcoleptic dogs with desirable traits. The narcoleptic dog colony is an absolutely necessary resource for current and future research projects. Not only will these projects help elucidate the neurochemical and genetic causes of narcolepsy, but they will also help define the mechanisms of symptoms, such as hallucinations and excessive sleepiness, which are present in other human illnesses. Investigations on narcoleptic animals also offer a novel approach to the understanding of the mechanisms of normal REM sleep.